The present invention relates generally to telecommunications systems and data networks, and more particularly, to systems and methods for establishing direct routing of a signal between communications devices and data networks using a digital loop carrier (xe2x80x9cDLCxe2x80x9d)
Telecommunications networks provide for both local calling within defined regions, and long-distance calling throughout the United States and other countries. These networks may be owned and operated by public and private companies, and governments. Some of these telecommunications networks are for the private use of the owning or operating entity. Others are operated by common carriers or by telecommunications service providers for use by the public or for use by a limited group of subscribers.
Various communications devices may be used to communicate over telephone lines of existing telecommunications networks. Some devices are based on analog technology, such as conventional telephones, since they are designed to support the analog waveforms of human speech. Other devices, such as facsimile (xe2x80x9cFAXxe2x80x9d) machines and personal computers, are based on digital technology because data processed by these devices is encoded and manipulated in binary strings of data. Personal computers may communicate over telephone lines using modems or other similar devices known to those skilled in the art.
Communications devices, such as telephones or modems, are generally connected to a service switching port (xe2x80x9cSSPxe2x80x9d) of a local telecommunications network through a pair of wires, generally referred to as a xe2x80x9csubscriber loop.xe2x80x9d A voltage is applied across the loop by the SSP to power the communications device, and to provide a mechanism for monitoring activity of the communications device. For example, when a calling party lifts the handset of a telephone to initiate a call, a switch in the telephone closes, enabling current to flow between the SSP and the telephone through the loop. The SSP detects current flow in the loop, and recognizes this as an xe2x80x9coff-hookxe2x80x9d condition. The SSP then transmits a dial tone to the communications device, thus allowing the calling party to dial the number of a called party, the intended recipient for the call.
As explained above, existing telecommunications networks allow for long-distance calling between local networks. Long-distance calling refers generally to the routing of calls over greater distances than those served by a local telecommunications network. For example, a calling party served by an SSP of a first telecommunications network may place a long-distance call to a called party served by an SSP of another telecommunications network over long-distance carriers such as fiber-optic networks. This is typically done by dialing a xe2x80x9c1xe2x80x9d before dialing the digits of numbers used by the called party.
Amplifiers have typically been used with circuitry for long-distance communication to compensate for signal attenuation as a call signal traverses long-distance circuitry. Because amplifiers are generally unidirectional, however, signals transmitted long-distance between telecommunications networks are generally separated into two distinct paths, such that signal transmission through each path is powered by a respective amplifier. One path is used for transmitting of call signals, and the other path is used for receiving call signals. Such signal splitting results in the use of a four-wire circuit, which is commonly referred to as a xe2x80x9ctrunk.xe2x80x9d
Various types of large capacity telecommunications networks have been specifically developed for the transport of data. These data networks typically use frame-relay (xe2x80x9cFRxe2x80x9d), asynchronous transfer mode (xe2x80x9cATMxe2x80x9d), Internet protocol (xe2x80x9cIPxe2x80x9d) or other packet-based technologies for data transmission. To send a data signal through a packet-based data network, the signal is first broken into individual blocks or xe2x80x9cpacketsxe2x80x9d of limited size. These individual blocks of data are then transmitted through the network and reconstructed upon receipt to form the original signal. The capacity of a data network is generally such that signals may be communicated through the network with minimal cost. Thus, if appropriate systems and methods of transmission are used, data networks may provide relatively cheaper alternatives to conventional telephone networks for local, and particularly long-distance, telecommunications.
Data networks are generally not designed to interface with existing telecommunications networks. This is because data networks typically communicate signals in the form of discrete packets or clocks of digital data, as explained above. On the other hand, telecommunications networks transmit telecommunications signals as continuous analog waveforms. Thus, to transmit an analog voice signal through a data network, for instance, the analog signal is desirably converted to digital form and then divided into blocks of appropriate size. These blocks of digital speech data are then communicated through the data network, individually. After the data blocks pass through the network, the blocks are reassembled, preferably in the order in which they were transmitted, to preserve any messages contained in the original analog voice signal. The reassembled digital voice signal is then converted back to an analog voice signal for communication to the called party.
A need has arisen for an efficient merger of a local telecommunications network, such as a publicly-switched telephone network (xe2x80x9cPSTNxe2x80x9d), with a data network. Most conventional techniques rely solely on the PSTNs and conventional long-distance publicly-switched telephone lines to establish the long-distance communications path. One example of a conventional long-distance communications system involves computers having video and audio capabilities. Each computer is coupled to a modem operating at, for example, V.34 modem speeds of approximately 33 Kbps. One of the computers calls from an originating telephone line served by a SSP of a first local telecommunications network, to another computer connected to a terminating phone line, served by the SSP of a second local telecommunications network. The connection between local telecommunications networks is made over a dedicated PSTN network trunk. Another example of a conventional long-distance telecommunications system includes xe2x80x9cFAXxe2x80x9d machines similarly served by respective telecommunications networks and communicating with one another through only PSTNs. These connections require costly equipment, including computers and FAX machines, and therefore are not universally used. A need therefore remains to provide efficient merger of a local telecommunications network with a data network.
Some techniques have recently been developed to support telecommunications over data networks such as the Internet. For example, a first private branch exchange (xe2x80x9cPBXxe2x80x9d) and a second PBX may be placed in communication with the data network. These PBXs may then be connected via an analog trunk to various communications devices. The equipment responds to dialing, presents a ring voltage when a call is received, and passes caller identification data to a called party for an incoming call. In addition, the equipment presents each PBX with call progress tones such as ring back and busy tones when outbound calls are made. However, limitations exist with this technique since this technique is private, that is, generally within a single organization and not available to the public.
One patent relates to establishing a call path between one PSTN and another PSTN over a data network. Specifically, Land et al. describes a xe2x80x9cSystem and Method for Establishing a Call Telecommunications Path,xe2x80x9d in U.S. Pat. No. 5,751,706. The system and method described by Land et al. allow for calls to be placed over packet-based telecommunications networks such as the Internet. As suggested by Land et al., however, calls are to be routed from a communications device such as telephone to a packet-based network through the switching equipment of a telecommunications network such as a PSTN. Land et al. does not disclose the establishment of direct call paths for routing calls from a communications device to the data network. Thus, while equipment exists which allows the transmission of telecommunications signals over a data network, the need for effective and efficient transport, i.e., direct routing of these signals to and from data networks, still exists.
Methods and systems according to exemplary embodiments of the present invention allow a user of a conventional telephone to dial a public switched telephone number through a data network. Connections may be established and calls placed on local, national and international levels. The principles of the present invention are applicable to various data networks, including both public and private data networks. Various types of data networks may be used, including the public Internet, private intranets, public and private FR networks, public and private ATM networks, SMDS networks, and various other digital carrier systems.
According to exemplary embodiments of the present invention, a local or long-distance call path may be established through the data network between various systems and communications devices, followed by two-way communication. Systems and devices that may be used include conventional telephone systems for two-way conversation, IP capable computers with modems, PBX networks, FAX devices, and various combinations thereof. For example, communication may be established between: conventional telephone systems or devices and an IP capable digital computer connected to a modem, a local telephone network and a PBX network, an IP capable computer and a PBX network, originating and terminating FAX systems or devices, originating and terminating IP capable digital computers, etc.
Methods and systems according to exemplary embodiments of the present invention involve connection methods and databases to manage resources at local telecommunications networks, digital loop carriers, and data network service providers to make compatible connections therebetween, and manage these connections. These connection methods and systems allow for direct connections between data network service providers and digital loop carriers, that is, xe2x80x9cline side directxe2x80x9d connections, both for incoming and outgoing calls to a called party or from a calling party, respectively, over a data network.
In one exemplary embodiment of the present invention, a digital loop carrier is coupled to a communications device, and coupled directly to a data network service provider in communication with a data network. In this way, a direct call path is provided between the digital loop carrier and the data network service provider for routing call signals between the communications device and the data network. The direct call path between the digital loop carrier and the data network service provider may bypass a default call path through a service switching port of a local telecommunications network.
In another exemplary embodiment of the present invention, a system is provided for establishing a communications path between a communications device and a data network. The system includes a data network service provider in communication with the data network, and a digital loop carrier coupled to the communications device. The digital loop carrier is coupled directly to the data network service provider to provide a direct call path between the digital loop carrier and the data network service provider for routing call signals between the communications device and the data network. A megahub controller may coupled to the digital loop carrier to control the routing of the call signals over the direct call path. The direct call path may be established for routing calls to the communications device and from the communications device.
In another exemplary embodiment of the present invention, a data network service provider has a plurality of paths for routing a call signal having one of a number of possible formats between a digital loop carrier and a data network. The possible formats may include voice coding, modem coding, facsimile coding, and other formats for routing telecommunications signals known to those skilled in the art. To this end, the data network service provider has circuitry configured to identify the format of the call signal and select one of the paths to carry the call signal based on the identified format.
In another exemplary embodiment of the present invention, a network topology identifying resources in a communications system may be maintained, for example, in a megahub controller used in a communications system. The communications system further includes one or more other megahub controllers, a plurality of data network service providers in communication with a data network, and a plurality of digital loop carriers coupled directly to the data network service providers. Databases, possibly in the form of routing tables, may be maintained on a recordable medium within one or more of the megahub controllers in the communications system identifying the megahub controllers, the data network service providers, the digital loop carriers, and various trunk groups coupled between the various components in the communications system. The digital loop carriers are preferably indexed by telephone numbers supported by the respective digital loop carriers.
One exemplary method of the present invention involves establishing a communications path between a digital loop carrier, which is in communication with a communications device, and a data network service provider in communication with a data network. In this way, a call signal may be carried between the communications device and the data network, for calls sent to and from the data network. The digital loop carrier is coupled to a service switching port of a telecommunications network by a communications line. The service switching port is coupled to the data network service provider. The service switching port has a call processing feature which, when activated by the service switching port, processes calls transmitted over the communications line. Exemplary call processing features include call forwarding, call waiting, and three-way calling. The method includes determining whether the service switching port has activated the call processing feature for the communications line, and establishing, if the call processing feature is inactive, the communications path using the direct trunk group. If the call processing feature is active, the communications path is established through the service switching port using the communications line.